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In the Name of
Allah, (P
hi
the Boundlessly Merciful, the Infinitely r
s
Compassionate. Praise be to Allah, the Lord of the
His Prophet
B a
worlds; and peace and blessings of Allah be upon
a n Muhammed
m r “Physical & General Geography (Paper I) for CSS & PMS” By Imran Bashir
Chapter 4: Earthquakes
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“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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Introduction.. Definitions
(P
i
“An earthquake is a shock or series of shocks
due to sudden movement of earth’s crust”.
h r
a s
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“An earthquake is the release of energy that
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has been slowly built up, during the stress of
a
increasing deformation of rocks.”
m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
Introduction…Cont
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• When Earthquakes
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Occur?
• Earthquakes occur
when energy stored in
hi
elastically strained
rocks is suddenly
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released.
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“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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Measurement of Earthquakes ..Cont
(P
hi r
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“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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Measurement of Earthquakes ..Cont
(P
FOCUS
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• The point beneath the surface where the rocks
break and move is called the focus. The focus is the
s
underground origin of an earthquake.
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a n • Directly above the focus, on the Earth’s surface is the
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epicenter. Earthquake waves reach the epicenter
EPICENTER first. During an earthquake, the most violent shaking
is found at the epicenter.
m “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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Seismic Waves
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Seismic Waves …Cont
(P
Types of Seismic Waves
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Surface waves
a s Body waves
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m r “Geography
Primary waves
for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
Secondary waves
& PMS” ByImran Bashir”
Imran Bashir
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Seismic Waves …Types of Seismic Waves
Body waves
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• There are two main types of body waves.
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• 1: Primary waves, also called P waves or compressional waves
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• 2: Secondary waves, also called S waves or shear waves
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“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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Seismic Waves …Types of Seismic Waves
Surface waves
(P
• L waves are the slowest moving
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of all waves, so the most
intense shaking usually comes
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at the end of an earthquake.
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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Measurement of Earthquakes
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Measurement of Earthquakes
Earthquakes are recorded with a
(P
seismogram
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a s
The magnitude of earthquake is
measured with Richter Scale
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a n Intensity of shaking is measured
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on the Mercalli scale.
m “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
How Do We Measure Earthquakes?
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Recent Major Earthquakes
PLACE YEAR CAUSALITIES
(P SIZE
i r
Pakistan 2013 500 approx. 7.8
h
Haiti 2010 316,000 approx. 7.0
Pakistan 2005
a s 80,000 approx. 7.6
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India 2001 20,000 7.7
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Turkey 1999 10,000 6.7
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Kobe,Japan 1995 5000 7.2
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Causes of Occurrence of Earthquakes
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4.
3.
P
Loss of Isostatic
Plate Tectonics
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Adjustment
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5.
2.
Accumulation of
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Volcanic Activity Water
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Causes of
1.
Occurrence 6.
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Elastic-Rebound
Theory of Other Causes
a
Earthquakes
m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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Size and Frequency of Occurrence
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Size and Frequency of Occurrence
Description Magnitude
(P
Frequency per year
i r
Great 8.0+ 1
h
Major 7.0-7.9 18
s
Large (destructive) 6.0-6.9 120
Moderate (damaging)
Minor (damage slight)
B a 5.0-5.9
4.0-4.0
1,000
6,000
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Generally felt 3.0-3.9 49,000
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Potentially perceptible 2.0-2.9 300,000
Imperceptible less than 2.0 600,000+
m “Geography for CSS / PMS ………. Author: Imran Bashir”
Earthquake Magnitude
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Earthquake Damage
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Earthquake Damage
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“Earthquakes don't kill people, buildings do”.
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1: 2:
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Ground
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8: Ground
Liquefaction Shaking Rupture
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a
7: 3:
Impacts on
Earthquake Fire
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Human Damages
a n6: 5:
4:
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Rapid Mass -
Tsunamis Landslides and Wasting
avalanches Processes
m “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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World Distribution of Earthquakes
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Predicting Earthquakes
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1: Dilatancy Theory
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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2: Animal Behaviour
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
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3: Early Warning System
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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4
a s
Radon Emissions
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
S)
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5: Other Prediction Methods .
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m r “Geography for CSS
“Physical & General / PMS
Geography ……….
(Paper I) for CSSAuthor:
& PMS” ByImran Bashir”
Imran Bashir
Earthquake Safety
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Protect yourself from falling objects (GET UNDER
SOMETHING) or stand in a hallway or doorway (watch out
P
for a swinging door).
r (
Do not try to go outside during the earthquake.
i
After the earthquake and before the aftershocks, go
outside.
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Do not return to the building until it has been inspected.
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